I'm actually completely different... In Pyung Ahn Sam Dan, I execute an out-to-in crescent kick followed by a stomp kick.
I prefer the crescent kick over the straight leg out-to-in because it's more realistic for self-defense. Out-to-in kicks look cool, are fun to break with, and work great for sparring when there are rules, but a crescent kick is far more devastating for an opponent who's out to kill you. Also, the crescent kick is much faster than the straight leg kick and leaves your groin and rear leg open for less time.
The stomp kick could be striking a knee joint, it also could be running down a shin (the ridges on the boots I wear would tear your flesh right open), it could be stomping the toes of an opponent (not a very good maneuver but still an option), and then, my favorite, the stomp can come down in the crest of the ankle. Stomping on the front of someone's ankle, just above the instep of their foot, is a traumatic strike. You can damage and even break the bones and strain the tendons. A rufian who has had their ankle crushed is far less likley to continue assaulting you. Remeber, the name of the game is not "tap the mugger with the out-to-in kick so I can win some points" (a good strategy for competition but that will get you killed on the street), but rather, "this guy picked the wrong person to choose for a victim today".
Back to the spinning back kick / spinning hook kick debate. My spinning back kick is a fast and effective technique. I can and will use this technique on the street. It involves the body spinning, risking disorientation, loss of balance, and unseen striking from the opponent for a very short time, but it is very powerful and in certain scenarios it is extremely useful (like when johnny mugger and his buddies have figured out that they are more likely to successfully rob a person if they all attack at the exact same time).
The spinning hook kick is like the back kick but the kicking leg begins the hook slightly after the middle point of the turn. The hook snaps in the front and then finishes like a regular hook kick. This kick is awesome for breaking (provides a lot of power and speed; Force equals mass times acceleration) and I've been very successful with the back hook kick in sparring for competition. I've never before used the spinning hook kick on the street. It wouldn't be much different than the back kick so I could see it working, but I personally prefer simplicity over finesse when it comes to training for life-or-death situations.
